RFR(S): 8202399:) [C1] LIRGenerator::do_CheckCast needs to exclude is_invokespecial_receiver_check() when using PatchAlot

[David Holmes]

Thanks Vladimir!

Much appreciated.

David

On 1/05/2018 9:48 AM, Vladimir Kozlov wrote:
> Reviewed.
> 
> Regards,
> Vladimir K.
> 
> On 4/30/18 2:30 PM, David Holmes wrote:
>> Thanks Vladimir! But as you actually supplied the patch details 
>> technically you can't self-review it. :)
>>
>> Can I get a "second" review please.
>>
>> Thanks,
>> David
>>
>> On 1/05/2018 7:12 AM, Vladimir Ivanov wrote:
>>> Looks good.
>>>
>>> Thanks a lot for taking care of it!
>>>
>>> Best regards,
>>> Vladimir Ivanov
>>>
>>> On 4/29/18 20:03, David Holmes wrote:
>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8202399
>>>> webrev: http://cr.openjdk.java.net/~dholmes/8202399/webrev/
>>>>
>>>> JDK-8168699 introduced  a special case for 
>>>> is_invokespecial_receiver_check() in LIRGenerator::do_CheckCast:
>>>>
>>>>    } else if (x->is_invokespecial_receiver_check()) {
>>>>      assert(patching_info == NULL, "can't patch this");
>>>>      stub = new DeoptimizeStub(info_for_exception,
>>>>                                Deoptimization::Reason_class_check,
>>>>                                Deoptimization::Action_none);
>>>>
>>>> but overlooked a potential bad interaction with PatchAlot. This can 
>>>> lead to  the assertion failure as observed during testing for 
>>>> JDK-8200167 with Graal. The proposed fix (supplied by Vladimir) is 
>>>> quite simple but needs to be applied to each of the CPU specific files:
>>>>
>>>> diff --git a/src/hotspot/cpu/x86/c1_LIRGenerator_x86.cpp 
>>>> b/src/hotspot/cpu/x86/c1_LIRGenerator_x86.cpp
>>>> --- a/src/hotspot/cpu/x86/c1_LIRGenerator_x86.cpp
>>>> +++ b/src/hotspot/cpu/x86/c1_LIRGenerator_x86.cpp
>>>> @@ -1314,7 +1314,7 @@
>>>>      LIRItem obj(x->obj(), this);
>>>>
>>>>      CodeEmitInfo* patching_info = NULL;
>>>> -  if (!x->klass()->is_loaded() || (PatchALot && 
>>>> !x->is_incompatible_class_change_check())) {
>>>> +  if (!x->klass()->is_loaded() || (PatchALot && 
>>>> !x->is_incompatible_class_change_check() && 
>>>> !x->is_invokespecial_receiver_check())) {
>>>>
>>>> Testing:
>>>>   - hotspot/jtreg/compiler (complete)
>>>>   - hs-comp-precheckin (once mach5 is available)
>>>>
>>>> Thanks,
>>>> David